full-disclosure - Re: OpenSSL-Bug still allows MITM, Browser(s) set up badly - Re: Identify weak Debian OpenSSL clients in SSH DH key exchange

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Message-ID: <20080526.13d63917d81a1cc6441bd6c06a86c34d@cynops.de>
Date: Mon, 26 May 2008 14:57:19 +0200
From: Alexander Klink <a.klink@...ops.de>
To: full-disclosure@...ts.grok.org.uk
Subject: Re: OpenSSL-Bug still allows MITM,
	Browser(s) set up badly - Re: Identify weak Debian OpenSSL clients
	in SSH DH	key exchange

Hi Niclas,

On Sun, May 25, 2008 at 09:15:55PM +0200, niclas wrote:
> you recently wrote that you tested the CA-certificates - but you didn't
> test the certificates which have been  *signed* by the CAs.

I actually tested a few of those and I also found one of a major bank
in Germany to vulnerable for a few hours ...

> I think all servers which had a vulnerable certificate, even for a short
> time, are still not secure - at least as long as the old certificates
> are still valid, which depends on the validity date saved in the
> certificate, only.

Indeed. The one for www.$major_bank.de is still valid for about 3 years.

> No, CRLs don't work. Firefox for example does not check for CRLs
> (default setting), making certificate revocation senseless. I assume,
> other Browsers don't check CRLs either. And what about the german

That is indeed a problem. AFAIK IE 7 on Vista now does some CRL checking
by default, but I haven't tried it yet.

> I think the only option is to change domain names. :-(

For phishing purposes and if we are talking about
www.$companyname.de/.com, this is obviously not a realistic option.

Cheers,
  Alex
-- 
Dipl.-Math. Alexander Klink | IT-Security Engineer |    a.klink@...ops.de
 mobile: +49 (0)178 2121703 |          Cynops GmbH | http://www.cynops.de
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